Double Bass NS Design CR - right-hand thumb rest?

[ToneRanger]

I've just bought a 2004 NS Design CR-4M in nice condition and am getting used to it. I've been playing BG, EUB and DB for years so generally have no problem with transitioning between instruments, but one thing I find challenging with this one: where do I put my right thumb?
(Note that I'm not talking about 'thumb position' with left hand)
On DB and my previous EUB, I hook my thumb under the edge of the fingerboard and can get a solid grab on the strings. On the NS, the fingerboard is flush with the body and only sits up about 4mm, so nothing much to rest the thumb on. I can use the mag pickup as a thumb rest but it's a bit too close to the bridge for comfort.
I'm wondering whether anyone has tips with technique and/or has attached some kind of thumb rest?

 

[Francois Blais]

Never tried that bass, but what about using the E string as the thumb anchor ? (when playing the other strings of course)
Maybe a piece of wood could be attached (with 3M stuff?) on the side of the bass for E string thumb anchoring?

 

[DoubleMIDI]

I think I used epoxy to glue some wood to the bottom of my free hanging EUB fingerboard because the edge was so thin that I constantly got blisters.
The former owner wanted the fingerboard more curved to get the same bowing angle (string to string) of a 4-string instrument on a 5-stringer.
Not really a good idea, but I got it for a reasonable price.
The result was a very narrow edge that my right thumb didn‘t like. So I glued a prepared piece of wood in the bass underside of the fingerboard smoothed the part that didn‘t fit exactly and are a lot happier playing that thing.

I‘m pretty sure 3M wouldn‘t have hold that together when I pluck.
I maybe would have used hide glue, but the underside of the fingerboard was not plan enough for that.

 

[Hummergeist]

I know it’s really inelegant, but in my NXT5a I put a couple of self adhesive rubber feet where the neck joins the body, and my thumb sits on those.

 

[DoubleMIDI]

If it works, it works.